Derek Johnson

DISEASES OF THE LOWER GI TRACT

BleedingDiarrhea/GI InfectionConstipationDiverticular DiseaseInflammatory Bowel DiseaseIrritable Bowel SyndromeIntestinal IschemiaCancer

DISEASES OF THE LOWER GI TRACT

Etiologies Diverticular Hemorrhage (33%) Neoplastic Disease (19%) – usually occult Colitis (18%) Angiodysplasia (8%) Anorectal (4%) Other – (postpolypectomy, vasculitis, brisk UGIB)

LOWER GI BLEED

Management Assess Severity Volume Resuscitation Transfusion Reverse Coagulopathy Lab Studies (H/H, PT/PTT, BUN/Creat,) Nasogastric Tube Endoscopy Radiographic Studies (RBC Scan, arteriography)

LOWER GI BLEED

Clinical Manifestations Diarrhea Tenesmus BRBPR Hematochesia

LOWER GI BLEED

GI Infections

Treatment Goals Replace Lost Fluids

Oral Rehydration Therapy Adults – Sports drinks, water, diluted fruit juice, broth Pediatrics – WHO recommends reduced osmolality oral rehydration solution

(Pedialyte, Infalyte, Rehydrolyte, Ceralyte) Eradicate the infectious agent Diagnosis

History (travel, antibiotic use, possible tainted food, sick contacts, HIV) Symptoms (blood in stool, vomiting, abdominal pain)

Viruses Rotavirus – most common cause of viral diarrhea in children

Similar rates of infection in developed and developing countries Large volume diarrhea without leukocytes in stool Fecal-Oral spread; common in daycares Treatment – supportive only Immunization (SOR A) – 3 doses; must be completed by 8 Months

Norovirus – leading cause of gastroenteritis in adults in U.S. (90% of outbreaks) Adenovirus Astrovirus CMV

Suspect in immunosuppressed or HIV

GI Infections

Bacteria Campylobacter

Tainted poultry and eggs; Most common cause in adults; Erythromycin if CX positive Shigella

Inflammatory diarrhea; Fecal-Oral spread; Bactrim (Peds) Fluoroquinolones (adults) Salmonella

Non-typhoid – self limiting; poultry and pet lizards; begins 6-48 hours after contact E coli O157:H7

Contaminated meat; Shiga toxin; marked Abd pain no fever; HUS; Supportive Care Vibrio

Contaminated Seafood; Doxycycline C difficile

Previous ABX exposure (amoxicillin, clinda, fluoroquinolones; Oral vancomycin or flagyl

GI Infections

Parasites Giardia

Contaminated water; profuse watery diarrhea; flagyl Cryptosporidia

Contaminated water; usually self limited; Cyclospora

Contaminated produce; Bactrim or cipro E histolytica

Contaminated food/water; liver abscesses; inflammatory, bloody diarrhea; flagyl

GI Infections

Colonic invastion Small Volume; cramping, tenesmus,

fever; Positive FOBT/WBC Etiologies

Bacterial Viral Parasitic

INFLAMMATORY

Disruption of the small intestine absorption and secretion

Voluminous; Negative FOBT/WBC Etiologies

Preformed Toxins S Aureus (meats/dairy) B cereus (fried rice) C perfringens (rewarmed meat)

Viral Bacterial Parasitic

NON-INFLAMMATORY

Acute Diarrhea

Etiologies of Acute Diarrhea

Chronic Diarrhea

Medications PPI, Abx, H2 blocker, SSRI, ARB, NSAIDS, chemo, caffeine

Malabsorption Whipple’s disease

Tropheryma whipplei; Tx – PCN + streptomycin, 3rd gen ceph, bactrim Small Intestinal Bacterial Overgrowth

Increased SI bacteria due to ileocecal valve dysfunction/absence Pancreatic Insufficiency

Chronic pancreatitis or pancreatic cancer Decreased Bile Acids

Due to decreased synthesis (cirrhosis) or cholestasis (PBC) Celiac disease

Gluten Ebola

Celiac disease Intolerance to the gliadin portion of gluten (wheat protein) Signs and symptoms

No typical presentation; Steatorrhea, anemia, failure to thrive, various deficiencies, bone loss, arthritis, neuropsychiatric disease

Labs CBC, Iron studies, Vit D, folate level Confirmatory tests – endomysial ab, IgA anti-tissue transglutaminase Ab, deaminated

gliadin peptide Ab (IgG/IgA) Histologic Confirmation – multiple proximal small intestine biopsies showing

flattened jejunal mucosa with villous atrophy

Chronic Diarrhea

Osmotic Lactose Intolerance – dx with hydrogen breath test; avoid lactose or supplement

lactase Inflammatory

Infection Inflammatory bowel disease

Secretory Hormonal – VIPoma, carcinoid, medullary thyroid cancer, ZE, glucagonoma Laxative abuse Neoplasm Lymphocytic/Collagenous colitis (associated with NSAIDS)

Chronic Diarrhea

Characterized by altered bowel habits and abdominal pain in the absence of structural abnormality

10-15% prevalence Due to altered intestinal motility/secretion in response to luminal

stimulation; associated with enhanced pain sensation Altered bowel habits

Alteration of diarrhea and constipation Constipation begins as episodic, becomes constant Evacuation feels incomplete Worsened with stress No nocturnal diarrhea

Irritable Bowel Syndrome

Patterns 80% diarrhea + constipation + pain 20% painless diarrhea

Symptoms Abdominal pain – episodic and crampy; does not usually interfere with sleep Gas and flatulence UGI symptoms – dyspepsia, heartburn, nausea, vomiting

Diagnosis Careful H&P Labs – CBC, iron studies, OCP, Stool leukocytes Endoscopy – if older than 40 to rule out cancer

Irritable Bowel Syndrome

Treatment Increase insoluble fiber; soluble fiber (psyllium) is ineffective Amitiza (lubiprostone) (SOR B) for constipation predominant; locally acting

chloride channel activator; increases intestinal fluid secretion Antispasmotics Antidiarrheals Antidepressants – TCS (SOR B) CBT (SOR B)

Irritable Bowel Disease

Constipation

Constipation

2 or more of the following over the previous 3 months Straining, lumpy/hard stools, incomplete evacuation, sensation of obstruction,

manual maneuvers to facilitate defacation, < 3 stools per week Etiology

Functional – slow transit, pelvic floor dysfunction, IBS Meds – Opiates; anticholinergics Obstruction Metabolic – DM, hypothyroidism, uremia, pregnancy, porphyria electrolyte

disturbance Neuro – Parkinson’s, Hirschsprung’s, MS, amyloidosis, spinal injury

Loss of intestinal peristalsis in absence of mechanical obstruction Precipitants – surgery, pancreatitis, peritonitis, sepsis, intestinal

ischemia Dx – Decreased/absent bowel sounds, discomfort, supine & upright

KUB, CT Treatement

NPO Mobilization NGT decompression Meds - neostigmine (colonic); methylnaltrexone (small bowel)

Adynamic Ileus

600,000 cases in the U.S Highest rates in Caucasians and Jews Pathogenesis

No known infectious role Some genetic role Immune role as mediator for tissue injury Disruption of intestinal barrier with changes in gut microbiota Acute inflammation without downregulation or tolerance

Inflammatory Bowel Disease

Ulcerative Colitis Incidence 1/10000; affects males and females equally; affects young adults Lower incidence in smokers Clinical features

Mild to severe at onset Aburpt onset Rectal bleeding, fever, pain, diarrhea, weight loss

Pathology Confined to mucosa Begins in rectum and spreads proximally without skip lesion

Inflammatory Bowel Disease

Ulcerative Colitis Diagnosis

Colonoscopy – 95% involve rectum; shows granular friable mucosa with diffuse ulceration

Microscopy – superficial chronic inflammation; crypt abscesses

Complications Toxic megacolon Correlation with colon cancer

Colonoscopy recommended every 1-2 years begun 8-10 years after onset

Inflammatory Bowel Disease

Treatment 5 ASA Derivatives

Sulfasalazine Mesalamine

Steroids Rectal Hydrocortisone Prednisone Methylprednisolone

Immune Modulators Infliximab (Remicade) Azatthioprine (Imuran)

Surgery Probiotics – promote remission

Inflammatory Bowel Disease

Crohn’s Disease Clinical features

Incidious onset Mild, mucous containing, non-bloody diarrhea Abdominal pain, fever, malaise, weight loss

Pathology Full wall thickness Any part of the GI tract can be affected

Small bowel (47%) Terminal ileum most common Ileocolonic (21%) Colonic (28%)

Inflammatory Bowel Disease

Crohn’s Disease Diagnosis

Colonoscopy/Small Bowel Imaging Nonfriable mucosa, cobblestoning Microscopy shows transmural

inflammation, mononuclear cell infiltrate, noncaseating granuloma

Complications Perianal disease Strictures Fistulas Abscesses Malabsorption

Inflammatory Bowel Disease

Crohn’s Disease Treatment

Antibiotics – fluoroquinolone/flagyl for perianal disease Sulfasalazine Steroids Infliximab Patient Education Surgery

Inflammatory Bowel Disease

Ischemia

Acute Mesenteric Ischemia Clinical Manifestation

Sudden abdominal pain out of proportion to exam Hematochesia Positive FOBT Intestinal Angina – early satiety, postparandial pain

Diagnosis High level of suspicion KUB – thumbprinting CTA Angiography

Acute Mesenteric Ischemia Etiology/Treatment

SMA Embolism – 50% have atrial fibrillation; SMA most prone to occlusion; tx with fibinolytic vs surgical embolectomy

SMA Thrombosis – clot at site of artery; percutaneous or surgical revasculization Venous Thrombosis – hypercoagulable states, malignancy, portal hypertension, IBD,

pancreatitis Non-occlusive – transient hypoperfusion (sepsis); remove offending pathology

Other treatments Anticoagulation Papaverine – local vasodilator infused by catheter directly in SMA

Ischemia

Ischemic Colitis Nonoccluive disease secondary to changes in systemic circulation often with

unknown etiology; Watershed areas most susceptible (splenic flecture and rectosigmoid)

Clinical manifestations LLQ pain with overtly bloody stool

Diagnosis r/o infectious colitis; consider flex sig if symptoms persist and no etiology identified

Treatment Bowel rest; IVF; broad spectrum Abx; surgery for infarction

Ischemia

Diverticulosis Acquired herniation of colonic mucosa and submucosa through the colonic wall 90% asymptomatic Intermittent LLQ pain Left Sided (90% mostly sigmoid) except in Asia 5-15 % develop diverticular hemorrhage Treatment – high fiber diet

Diverticular Disease

Diverticulitis Clinical Presentation

Acute lower Abd pain; possible acute abdomen with peritoneal signs Fever Tachycardia

Pathophysiology Retention of undigested food > fecalith formation > obstruction > compromise of blood

supply > infection > perforation (abscess, fistula, obstruction) Diagnosis

Lab – CBC, CMP, CRP (>50 with abdominal pain highly suspicious) Xray – plain films checking for free air CT - >95% SP & SN Avoid Endoscopy – Colonoscopy 4-6 weeks following resolution

Diverticular Disease

Diverticulitis Treatment

Non-severe – Clear liquids with oral Abx (Cipro or flagyl) Severe – NPO, NGT, IV fluids, narcotic pain relief, IV Abx

Ampicillin + Aminoglycoside + flagyl Primaxin Zosyn

Surgery – for prolonged symptoms despite proper Rx Percutaneous drainage of abscesses >4 cm

Prevention Low fiber diet after acute episode; resume high fiber 6 weeks after resolution of symptoms If recurrent consider mesalamine +/- rifaximin

Diverticular Disease

Small intestinal cancer Rare Most common with Crohn’s disease Adenocarcinoma most common Diagnosis – CT Treatment – Surgical Resection

Cancer

Colon Polyps Presentation – usually asymptomatic; may bleed; obstruction possible Diagnosis – endoscopy Treatment – removal during colonoscopy; if visualized on flex sig reflex to

colonoscopy Cancer correlation

<1 cm - <1% chance of malignant conversion 1-2 cm – 10-20% chance of malignant conversion >2cm – 30-50% chance of malignant conversion

Cancer

Tubular Adenoma

Cancer

Villous Adenoma

Cancer

Tubulovillous Adenoma

Cancer

Hyperplastic polyp

Cancer

Hamartoma

Cancer

Inflammatory polyp

Cancer

Colon Cancer 2nd most common cause of cancer death 1/17 lifetime risk More common in Western nations Up to 25% of patients have positive family history

Familial adenomatous poluposis – mutation in APC gene; 100% lifetime risk Hereditary nonpolyposis colorectal cancer; mutation in DNA mismatch repair genes;

predominantly right sided tumors Equal distribution male/female, Caucasian/African American; higher mortality

rate in African Americans 95% Adenocarcinoma

Cancer

Colon Cancer Predisposing factors

Age Family HX IBD Polyposis – FAP, HNPCC, Peutz-Jeugers Diabetes Cholecystectomy Streptococcus bovis endocarditis High fat low fiber diet

Cancer

Colon Cancer Screening Start Age 50 or 10 years before sentinel event in family history Recommended age 50—75 (average risk) Screening rate currently 58.6% (goal is 70%) Methodology

Colonoscopy – repeat 10 years if negative Flexible Sigmoidoscopy – repeat 5 years FOBT – yearly Double Contrast Barium Enema – 5-10 years

Cancer

Repeat colonoscopy

Cancer

Colon Cancer Treatment Surgical excision – 5 cm margins Clearing colonoscopy; repeat 3-5 years Chemo

5-FU Irinotecan Oxaliplatin

Radiation for metastasis

Cancer

A 19-year-old man on vacation with his family drinks water from a stream in Yellowstone National Park. Forty-eight hours later, the patient develops profuse watery, malodorous diarrhea, severe abdominal cramps, vomiting, and fatigue. The patient is clinically diagnosed with Giardia lamblia and treated empirically with metronidazole. The patient improves initially, but over the next 4 weeks, he develops a more chronic picture of intermittent bloating, gas, and watery diarrhea after eating and returns for further management. What is the most likely cause of this patient’s ongoing symptoms?

(A)Chronic Giardia infection (B)Crohn’s disease (C)Lactose intolerance (D)Misdiagnosis with ongoing parasitic infection from a non-Giardiaorganism (E)Ulcerative colitis

Question 1

(C) Lactose intolerance. This patient’s initial diagnosis ofG. Lamblia infection is likely correct

given his history and clinical presentation. Chronic infection with Giardia is uncommon, as metronidazole therapy is usually curative. Lactose intolerance, which can be prolonged, frequently develops following Giardia infection and has very similar symptoms. Ulcerative colitis and Crohn’s disease would likely have a more severe symptom profile and are not associated with

Question 1

A 22-year-old man presents to the emergency department with severe abdominal cramping and bloody stools. He states that he initially had nonbloody diarrhea for several days. He has mild, diffuse abdominal pain and a low-grade fever. He has marked leukocytosis and is also found to be in acute renal failure, likely from dehydration. He is admitted to the intensive care unit where aggressive supportive therapy is instituted. Studies of stool specimens demonstrate infection with enterohemorrhagic Escherichia coli0157:H7. Which of the following antibiotics should be used to treat this organism?

(A)Ceftriaxone (B)Ciprofloxacin (C)Levofloxacin (D)Trimethoprim-sulfamethoxazole (E)No antibiotic therapy should be instituted

Question 2

(E) No antibiotic therapy should be instituted. The patient is infected with E. coli0157:H7. In general, antibiotic

therapy has not been shown to be helpful in such cases. Antibiotic therapy does not appear to shorten the clinical course of the infection and also does not appear to reduce the incidence of hemolytic uremic syndrome, which can develop in patients with this particular infection. Thus, treatment of E. Coli 0157:H7 infection is largely supportive.

Question 2